Oligosaccharide residues on the AIDS virus coat protein may determine one or more of the multiple processes that govern infectivity. These complex carbohydrates might, for example, contribute to protein stabilization by protecting against antibody binding or might play a more direct role as receptors. Our two complementary research groups, which combine techniqueS in molecular biology and glycoprotein analysis, propose to collaborate to resolve the Structure and functional implications of the coat protein, gp120. Thus, preparation and growth of site-directed mutants will be pursued by virologists experienced in AIDS virology. These biological efforts will be supported by another group experienced in the detailed structural analysis of oligosaccharides using mass spectrometry and related adjunct techniques. The proposal has three primary goals: (1) To define glycosylation sites on natural- and recombinant-gp120 isolates; (2) To prepare site-directed mutations/deletions at these sites and study their biological activity; and, (3) To provide a detailed structure of glycopeptide residues at the functionally active sites. Preliminary data have been gathered using recent analytical developments that markedly increase specificity and sensitivity and that therefore make these structural approaches feasible; e.g., (i) Oligosaccharide capillary column separations using supercritical fluid chromatography (SFC), (ii) Direct MS interfacing of this chromatograph (SFC-MS), and (iii) MS ion detection using focal plane ion detection (FPID). The sensitivity of the available instrumentation will be further enhanced by using negative ion chemical ionization MS. These advanced analytical techniques, together with those of molecular biology, should enable us to provide insight into how complex carbohydrates may be involved in viral binding, fusion, anchorage, subunit association, and processing. Such information, by providing a better understanding of glycoprotein structure-functional relationships, may be the basis for such practical applications as vaccine design.